PROJECT ABSTRACT Modern ophthalmic surgery depends on the stereo microscope for surgical field visualization to the extent that procedures best performed from alternate viewpoints are difficult if not impossible due to an inadequate view and non-intuitive surgical maneuvers. We seek to overcome limitations which physically couple the surgeon to both the stereo microscope and hand-held surgical instruments. This current paradigm causes ophthalmic mi- crosurgeons to frequently perform manually awkward maneuvers due to a limited, fixed point of view and limits in maneuverability imposed by the port based nature of these procedures. Under previous NIH support, Dr. Izatt?s group has been the leading academic research group introducing optical coherence tomography (OCT) technol- ogy into the operating room. Their microscope-integrated OCT (MIOCT) system design displays live 3D volumes of the surgical field in real time, viewed by the surgeon via a stereoscopic heads-up display or stereoscopic monitor, and can be interactively rotated, scaled, and zoomed to arbitrary viewpoints by the surgeon using foot joystick control. The ability provided by MIOCT for the surgeon to view the operative field from any viewpoint provides a revolutionary opportunity to intuitively increase the microsurgeon?s manual dexterity, range, and pre- cision by coupling live 3D imaging technology with interactive robotic manipulation of surgical instruments. We propose development of a technology we term Arbitrary Viewpoint Robotic Surgery (AVRS), which provides an intuitive interface for the surgeon to perform surgical maneuvers using a haptic interface from his/her preferred point of view, while these maneuvers are computationally translated to the surgical frame of reference and per- formed interactively using precise robotic manipulation. In addition to operating from an optimal dynamically adjustable viewpoint, AVRS would also provide for the surgeon to operate at a comfortable range scale through motion minification, for simultaneous control of an arbitrary number of surgical instruments, for techniques for surgeon tremor and patient motion removal, and for reduction in surgeon discomfort and fatigue through ergo- nomic design of visual and haptic interfaces. The proposed project includes the following specific aims: 1) De- velop and demonstrate technology for AVRS using live volumetric OCT imaging, and 2) Characterize the perfor- mance of the AVRS system and perform realistic ophthalmic microsurgical maneuvers in animal and cadaver eyes. The expected outcome of this proposal is a suite of technologies with potential to enhance ophthalmic microsurgical technique by overcoming viewpoint, port, and hand position limitations. These technologies will facilitate surgeon training, advance the skills of experienced surgeons, and thus potentially improve surgical outcomes for all patients. Further, we believe that development and demonstration of these technologies for ophthalmic microsurgery will develop concepts readily transferable to other surgical applications, such as neu- rosurgery or laparoscopic surgery, that may benefit from live 3D guidance using OCT and other imaging tech- niques.